Almost 150 residents and staff members at one nursing home fell ill in recent weeks with sniffles and other symptoms much less severe than the headaches and pneumonia associated with severe acute respiratory syndrome.
Most have completely recovered, but six of the nursing home residents have died of pneumonia-related illness. The latest death, reported Tuesday, was an elderly woman who had typical pneumonia symptoms rather than the distinct pneumonia symptoms of SARS, officials said.
Three of the dead and an unspecified number of others sickened at the Kinsmen Place Lodge in Surrey, a Vancouver suburb, tested positive for coronavirus, the kind associated with SARS, noted Dr. David Patrick, director of epidemiology at the B.C. Center for Disease Control.
If this truly is the SARS coronavirus, "we're definitely uncovering a different pattern of illness than the one described in the spring," Patrick said at a news conference Tuesday. It could be a mutated SARS coronavirus that has lost virulence, he said, a favored hypothesis among many experts.
Dr. Roland Guasparini, chief medical officer for the Fraser Health Authority, said scientists were checking a handful of possible similar cases at a second, unspecified facility.
WHO virologist Dr. Katrin Leitmeyer arrived Tuesday in Winnipeg, Manitoba, to work at the national disease laboratory on tests of the virus detected in British Columbia, WHO spokesman Iain Simpson said Wednesday in Geneva.
"The question is: Was this indeed the coronavirus that causes SARS?" Simpson said. "If so, how come it hasn't caused SARS as we understand it in this case, and if not how come the test results came back positive?"
He said the decision to send Leitmeyer was a joint agreement between WHO and the Canadian government.
Canada's largest city, Toronto, was the epicenter of the biggest SARS outbreak outside of Asia, with almost 250 people sickened and 44 of them dying this year. Only four confirmed SARS cases have been reported in British Columbia, more than 1,000 miles west on the Pacific coast.
The Toronto SARS outbreak brought a WHO warning against non-essential travel to the city, which caused economic harm by devastating the spring and summer tourism industry.
Fear of further economic problems from another Canadian SARS outbreak may be causing authorities to play down the British Columbia situation, warned Dr. Henry Niman, a Harvard Medical School surgery instructor who has closely followed the global SARS epidemic.
Even as the SARS threat subsided this summer, disease experts warned it could return when the weather turns cold — when respiratory diseases typically flourish.
Worldwide, SARS sickened 8,422 people, according to WHO, and killed 916. More than 1,700 of those who contracted the disease were health care workers. In China it led to large quarantines. In Singapore, Hong Kong and elsewhere, it prompted airports to take passengers' temperatures, and for people to wear surgical masks on the streets.
As of the end of July, the Centers for Disease Control said it had received reports of 192 possible cases of the disease, only 33 of which were strongly suspected of actually being SARS.
Thirty-five states reported cases but most noted only a handful of cases, except for California and New York. Thirty-six cases were reported in California and 33 in New York.